Retro? Or Way Ahead?

In Sept./Oct 1970, I designed and tested the removable Tri-Fin system I called PressLock. By Feb. 1971, the Lexan, injection molded fins (2’’ deep, 2’'base) were available to other surfboard builders. (Hobie, Bing, Weber, etc.) The system used no screws, tools, or glue, to hold the fins in the board. The ‘‘box’’ was molded into the board in the hotcoat stage, prior to sanding. Back then the foam was of a much higher density, and gave excellent support to the molded box. Because of a recent request for that system, in a modern board with lower density foam, I redesigned the routed slot into which the ‘‘box’’ is molded. The ‘‘box’’ is now very well supported, in the lighter weight foam. I still have about 15 sets of those original fins, so can still make a few boards with them, or put some into existing boards. I’m not beating the drum to sell any of them, just passing along something some of you may find interesting. Sort of a what’s old, is new, story.

Way ahead Bill.

You saw the future.


Very cool Bill. What was the motivation for a removable back then?  Probably not travel right?  Use different fin?

   The primary reason was to be able to put them into new boards, and to  retrofit existing boards.    As well as enable them to be removed, if only a single fin was desired.   It also made shipping multiple boards, in a single box, a little easier.     For something like Pipeline, only the left rail side fin could be used, for a better bite into the wave face.    I guess you could sum it up as versitility.

At that time I had a Surfboard shop in Torrance and was buying your fin system through Dewey Weber. I designed a 6’3" pintail for your system that was an amazing board. I loved your system and it help me sell boards. One of my team members shredded with them. WOW Deja Vu… those were great days!



Dewey Weber was the first major builder to contact me, when I brought out that fin system.    Yep, those WERE great days.     There seemed to be something new on a weekly basis.

Dude, like trifins andfin boxes are likeold news.  theier like over 30years old or somethign. its morelike something old and something even older.

By way of update: I’ve done a recent redesign on the routing process, to provide a flange on the ‘‘box’’ for additional support in todays lower density foam.    I’ll also be putting some of the original fins into a few age appropriate 70’s boards, for a collector.     These fins are THE progenitors of the 3 fin configuration that became surfboard orthodoxy for so many years.     By the end of 1971, we had done boards with 4, 5, 6. and 7 fin configurations, using that fin system.     I learned alot about the how and why of fin function, and surfboard performance.    Folks are still plowing the same ground that was plowed decades ago.

been working with pure acrylic lately…need to make some more molds…my best to you !!!



Aloha Herb, I assume you refer to your MVG’s.     Acrylic?     Cold pour, or hot pour?   

cold pour…it’s easier to deal with…super tough.

All is good here…wishing you the same…my best !



Was this before Richard Brewer made his Tri Fin ?


    Greg, I did my first Tri Fin in late August 1964.     Found it interesting, but much more loose than the then ‘‘normal’’ pushback from the standard   D  fin of the day.    I  did my prototyping of the removable Tri Fins in early October 1970.     I don’t have a timeline on what Dick was doing, or when he was doing it.      The 1964 configuration was what today is call a thruster setup.      Three equal size mini reverse fins.    Total surface area was equal to a single reverse  D fin.     Hard to believe that was a half century ago.

I think it was Christmas 70-71 when I made a twin on Kauai getting some fins made at Brewers shop .

He had Tom Stones cover shot Balsa Diff as a Trade in . I don’t think Brewer ever made Twins even tho they were the rage at the time . Shortly after he started making his Tri fin with reports of Liko Boy doing turning 360’s at Hanalei  on them :slight_smile: